I am using HIbernate3.2.0cr2 with hibernate-anntations-3.2.0

I have the foll . use case :

Student ------ Registrar ---------College


I am using annotations for specifying many-to-many relationship via the association table "Registrar"


Here are the POJOs :

Student.java :
@Entity
@Table(name = "tbl_student")
@Inheritance(strategy=InheritanceType.JOINED)
public class Student implements Serializable {


private static final long serialVersionUID = 1L;

private Long id;

private String name;

protected Set colleges = new HashSet();

public Student() {

}

@Column(name = "student_name", nullable = false, length = 50)
public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
public Long getId() {
return id;
}

public void setId(Long student_id) {
this.id = student_id;
}

@ManyToMany(
cascade={CascadeType.PERSIST, CascadeType.MERGE},
mappedBy="college",
targetEntity=College.class
)
public Set getColleges() {
return colleges;
}


}



College.java :
@Entity

@Table(name = "tbl_college")

@Inheritance(strategy = InheritanceType.SINGLE_TABLE)

@DiscriminatorColumn(name = "college_type",
discriminatorType = DiscriminatorType.STRING)

public class College implements Serializable {


@ManyToMany(
targetEntity = Student.class,
cascade = { CascadeType.PERSIST,CascadeType.MERGE }
)
@JoinTable(
name = "TBL_REGISTRAR",
joinColumns = { @JoinColumn(name = "COLLEGE_ID") },
inverseJoinColumns = { @JoinColumn(name = "STUDENT_ID") }
)

public Set getStudents() {
return students;
}

protected Set students = new HashSet();

private static final long serialVersionUID = 1L;

Long college_id;

private String name;

public College() {

// TODO Auto-generated constructor stub
}

@Column(name = "college_name", nullable = false, length = 50)
public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
public Long getCollege_id() {
return college_id;
}

public void setCollege_id(Long college_id) {
this.college_id = college_id;
}

}


Registrar.java:
@Entity
@Table(name = "tbl_registrar")

public class Registrar implements Serializable {

private static final long serialVersionUID = 1L;

public Registrar() {

}



}

I am getting this exception :
Caused by: org.hibernate.AnnotationException: mappedBy reference an unknown property: com.webify.registration.domain.College.college in com.webify.registration.domain.Student.college

Pls help me with the mapping?

Change to:
mappedBy="students"